class Maybe {
    static of (value) {
      return new Maybe(value)
    }
  
    constructor(value) {
      this._value = value
    }
  
    map (fn) {
      return this.isNothing() ? Maybe.of(null) : Maybe.of(fn(this._value))
    }
  
    isNothing() {
      return this._value === null || this._value === undefined
    }
}

class Container {
  static of(value) {
      return new Container(value)
  }
  
  constructor (value) {
      this._value = value
  }

  map(fn) {
      return Container.of(fn(this._value))
  }
}

exports.Maybe = Maybe
exports.Container = Container

